1. Field of the Invention
The present invention relates generally to demultiplexing large numbers of channels, and more particularly, to demultiplexing nested sets of frequency division multiplexed (FDM) channels.
2. Related Art
The polyphase-discrete fourier transform (PPF-DFT) filter bank is widely recognized as the most computationally efficient means of demultiplexing a group of uniformly spaced frequency division multiplexed (FDM) channels of equal bandwidth. However, many applications require a prohibitively large number (e.g., much greater than 32) of FDMchannels to be demultiplexed.
Unfortunately, directly demultiplexing a large number of channels requires a higher order PPF-DFT filter bank, which in turn can only be implemented with higher coefficient and arithmetic bit widths. Increasing coefficient and arithmetic bit widths increases implementation power and mass; two precious commodities in short supply on communications satellites.
It is desirable therefore that a computationally efficient method to demultiplex a plurality of nested sets of FDM channels that overcomes the shortcomings of conventional methods be provided.